Improvement in drawing-board trestles



'1. H. HABDEN.

Drawing-Board Trestles. N0. 145,174, Patented Dec. 2,1873.

UNITED STATES PATENT OFFICE JOHN H. HARDEN, OF PHILADELPHIA, PENNSYLVANIA.

IMPROVEMENT IN DRAWING-BOARD TRESTLES.

Specification forming part of Letters Patent No. 145,l74, dated December 2, 1873; application filed May 31, 1673.

'To all whom it may concern.-

Be it known that I, JOHN H. HARDEN, of Philadelphia, Pennsylvania, have invented an Improved Drawing-Board Trestle, of which the following is a specification The object of my invention is to so construct supports for a drawing-board that it can be readily adjusted to different heights and different angles. i

This object I attain by means of the trestles illustrated by the perspective view inthe accompanying drawing, the bar A of each trestle being so secured to the stand B that the former can be adjusted vertically andto difl'erent angles, and secured after adjustment. The stand B of each trestle is composed of the two horizontal and parallel bars, so connected together that there shall be between them an intervening space for the reception of the appliances described hereafter as appertaining to the adjustable portion A. Two inclined legs, I) b, are connected to the bar a, and two similar legs, d d, to the bar, a, the legs b and 11 being connected together near their lower ends by a cross-bar, e and the legs b and d being connected together by a similar crossbar 0; and a diagonal brace, f, extends from the cross-bar e to the center of the bar a, a similar brace, j, extending from the crossbar c to the center of the bar a, and the upper ends of the braces and the two bars a and a being secured together by a bolt, h. The adjustable portion A of the trestle consists of two parallel bars,i and i, so connected to gether that there shall be a space between them for the admission of the upper ends of the two slotted segments m and m, and the upper end of a central plate, each segment .being hinged to the bars by a bolt, 1), and the bars being hinged to the central plate by a bolt, q, while a bolt, t, passes through the slot of each segment and through the bars a and a. which embrace the segment, the central plate n being confined between the bars a a. of the stand by bolts w w, which pass through Vertical slots in the said plate. When the nuts of the bolts t t have been loosened,

the movable portion A of the trestle is free to be vibrated on the central bolt q, and hence can be adjusted to any desired inclination, either of the ends being depressed as circumstances may require.

This adjustability of the top of the trestle is a great accommodation to the draftsman, especially when large boards are employed, in which case it may be necessary for him to change his position from one side to the opposite side of the board, and to incline the latter.

The altitude of the movable portion of the trestle may be changed after loosening the nuts of the bolts to w, as well as those of the bolts t t, and then raising the central plate a.

I prefer to hinge each segment m to the bars 1' i, in the manner described and illustrated, so that it will accommodate itself to any altered relative positions of the bolt q and bolts t, caused by any change in the altitude of the upper portion of the trestle; each segment, however, may be permanently secured to the bars 1 1", in which case it will be necessary for the bolts t t to be self-zuljusting in slots in the bars a and a of the stand B.

I claim as my invention- 1. A drawing-board support, consisting of two bars, A A, adjustable horizontally on central pins q, and vertically on independent trcstles, as set forth.

2. A stand, B, having bars a a, and a plate, a, adjustable between the bars, in combination with bars i i, hinged to the said plate, and having segments on m adapted to bolts t t in the bars a 11 of the stand, all substantially as described.

3. The structure composed of the bars a a, legs I) b and (Z d, cross-bars e c, and inclined braces ff, all fitted and secured together in the manner described.

In testimony whereof I have signed my name to this specification in the presence of two sub scribing witnesses.

JOHN HY. HARDEN.

Witnesses: I WM. A. STEEL. I-IUBERT HowsoN. 

